Fine lines disappear

Your printer draws in lines about as wide as its nozzle, and nothing narrower than one of those lines can be drawn at all. Filafy already sizes every style so its patterns, strokes and dots survive the nozzle you set. A photograph can still leave a hairline between two colors that is finer than any line your printer owns.

When that happens your slicer decides for you, quietly. It cannot form the sliver. Bambu Studio, OrcaSlicer and Anycubic Slicer Next then print that area in filament 1, your base color, without telling you. On a dark image over a bright base, this shows as bright specks. The image you approved and the piece on your plate stop matching. To hide the specks, make the color around the detail your base color.

Filafy suggests that base color. When one color surrounds most of the detail too thin to print, a note names that color. The note is under Background / base color on the Filament & colors tab. A coral dot on the tab tells you the note is there. Click the note's button to make that color your base. Everything the image does not cover then prints in that color too.

Merge details too thin to print, on the Print setup tab of the Design step, makes that call in Filafy instead. Every region too fine to take one line joins the color it shares the most edge with. It happens during the conversion, so the live preview, the PNG, the SVG and the 3MF all show the same image. All four land closer to what comes off the plate.

The point is a simpler, more reliable print. Fewer sliver-thin features means fewer places for a print to go wrong. There is less stringing chasing lines that were never going to form, and fewer filament swaps spent on detail that will not appear. The result is closer to what you saw on screen.

Set your nozzle first. The nozzle is what sets the line width, so it is also what sets how much this merges. The same image folded for a 0.8 mm nozzle loses noticeably more than the same image folded for 0.2 mm.